Method of converting potassium chloride into potassium sulphate



Aug. 15, A HOLZ 1,922,682

METHOD OF CONVERTING POTASSIUM CHLORIDE INTO POTASSIUM SULPHATE Filed Aug. l5, 1931 l BY l mg/@m Patented Aug. 15, 1933 UNITED STATES PATENT` oFF-loef 13225821 Y ,METHOD or'` 4coNvER'rINof PorAssioM CHLORIDE INT0 PoTAssIuM sULrHA'rE August Holz, Irving-ton, Y Application August 1931. seriaiNatsmoo 1 claim. (or lzii-121) My present invention relates to a method of, andmeans for, converting-potassium chloride into the corresponding sulphate and nitrate salts.

In myco-pending. applicationSerial No. 476,-, 5 449,:f1led August`19, 1930, there is disclosed acornpotassium is readily'available inlarge quantities at relatively economicalprices. It will, therefore, be seen that a successful method of Aconverting potassium chloride tothe sulphate'of potassium would be of great 'value tothe method described Ain said co-pending application.

Now, I have discovered a commercially feasible,

and highly novel, process of, and `devised meansY for, eiecting the conversionor potassium chloride into potassium sulphate, while simultaneously utilizing by-products of the conversion to produce an essential ingredient of conversion reaction mixture. l y

Accordingly, it may be vstated that it is one of the main objects of my present vinvention to Vprovideia method of, and means for, treating potassium chloride consisting in reacting the latter with ammonium sulphate, the, reaction being maintained at a temperature'above the volatilization point of ammoniumchloride and below the melting point of potassium sulphate, treating the condensed ammonium chloride to` liberate ammonia, and'utilizing the latter to form additional ammonium sulphate thereby establishing a complete production cycle.

Another important object of this invention is to provide an apparatus for economically effecting the present conversion 'process in a con-` tinuous cycle, the apparatus generally comprising a conversion chamber designed to receive the reaction materials at one end thereof Vand slowly feed the reacting materials towardsa point where the desired converted material is delivered, the

Still other` objects of the present Vinvention areV to provide a novel method of converting potassiumchloride into potassium sulphate, the'latter being used for the'Y production of .potas-V sium nitrate, Vthereby creating an economical source of materials for said nitrate production, `and to, moreover, carry out said conversion process in asimple, and eicient aparatus whereinthe'conversion proceeds in a continuous mannerby yvirtue oi e complete utilization of conversion,by-products` The novel features Whi h I believe `to be characteristicof my invention are set forth in par-Y ticularty in theA appendedclaim, theminvention itself, however, as to bothits .apparatus and` method of operation will best be understood by reference to the following descriptlontakenin connection with the drawing in whichl have schematically indicated, an apparatus" whereby my invention may be carried into effect. Y

In the drawing; Fig. l is avschematic representation of an arrangementor carrying out the present process; .,Fig. 2 isa detail view oi a section of the conversionchamber. ,Y g

Referring now, to the accompanying drawing in which like characters of reference indicate the 4 same parts in the two gures, the flow sheet. diagram of Fig.1rshows a conversion chamber l, preferably made of iron, in the formof, a. longMinclined, fixed cylinder. Thev latteihas disposed within its interior 2, af helical feeding. device 3, the latta-.being mounted upon an inclined shaft y4. The shaft is rotatably supported in bearings at opposite ends of the` chamberV 1, and f driven `by any well known, means (not shown) It is not believed necessary to describe the feed `device in any further detail` since those skilled inthe art are acquainted with this ex-` pedient for Vslowly transporting a reacting mixture from one end of a chamber to another.

The higher end of the chamber l is'provided* with an opening, equipped with a feed hopper 5 at the lower portion of said end, if desired, to receive predetermined quantities of the potassium chloride and ammonium sulphate.l The chamber is maintained at a ,predeterminedV reaction temperature by any desired means. Superheated steam` may be injected into the interior of the chamber at the lower end thereof` through an opening ,6 `provided above the helical feed 3 for moving gases. The reaction temperature is such thatthe vconversion proceeds according to the following equation: v

{I he temperature isv above' the Volatilization point ofthe ammonium chloride, but far below the melting point of the potassium sulphate. ,An outlet llis, thusprovidedat the upper end `of the chamber, above the helicalrfeed, whereby the volatilized ammonium chloride readily escapesv from the conversion chamber. On the other hand, an 'outlet 8 is provided at the lower end of the chamber, below the helical feed, .to permit the deliveryof potassium sulphate. The latter is delivered ih a pulverulent state.

vice 3 is eccentrically disposed with respect to the axis of the cylinder. Fig. 2 shows, in detail, the manner in which this is done. The cylinder' has an elliptical cross-section, and due to the said eccentric arrangement, a considerable space 9 is provided between the upper side of the cylinder and the helical drive between inlet 6 and outlet 7, while little clearance 10 is provided between the lower side ofthe cylinder Yand the helical drive between the outlet 8 and hopper 5.l

The cylinder 1 is provided with a siliceous lining 11. The inlet 6 while admitting steam for aiding removal of volatilized ammonium chloride from the chamber, may admit air under pressure,

' stant rate, while the speed of the helical device 3 is regulated to deliver a predetermined quantity of pulverulent potassium sulphate per desired unit of' time. The ammonium chloride fumes, as pointed out, are forced out of the chamber space 9 into the outlet 7. A conduit 12 guides the fumes into either one of a pair of condensing chambers -13, 13.

Thus, the fumes are led into chamber 13 through a pipe 14 and. Valve 15, while pipe 14 and valve 15 guide the fumes into chamber 13.Y Each chamber is partly iilled with water, shown by dotted lines 16, 16', the pipe outlets in each chamber terminating below the water level. Any well known type of vacuum producing mechanism, conventionally represented by the numeral 17, provides'suction for the chambers 13 and 13', as shown, thereby facilitating the sweeping of fumes from the conversion chamber into the condensing chambers.

The chambers 13, 13 are operated alternately. That is, while the fumes are-being condensed in one chamber, the other chamber is being emptied. Thus, assuming chamber 13 to be condensing fumes, thevalve 15 would be open, while the valve 15 would be shut. Each chamber is provided at itstop with any well known type ofV water spraying device 18, 18 it being understood that when fumes enter a chamber they are cooled and instantly dissolved in the i'lne spray through which they must pass. When a chamber, say 13, contains a suiiiciently saturated solution of ammonium chloride, the Valve 15 is shut, valve 19 opened, valve 15 opened,.and valve 19 closed. A pump 20, preferably a centrifugal type of pump, is connectedY throughk the valves 19, 19 to the outlets of thev chambers 13, 13. The pump 20 discharges solution, through conduit 21, into an ammonia distilling chamber 22 through an inlet 23.

Through a hopper 24, at the top of the chamber 22, there is continuously fed calcium; oxide (CaO) into the chamber. The oxide is slaked by the water of the ammonium chloride solution, and the resulting reaction follows the following equation:

The liberated ammonia gas is permitted to escape through the outlet 25. An outlet 26 provides for the removal of the calcium chloride solution. Y 1 The liberated 'ammonia gas is passed into a sulphuric acid absorption chamber 27 constructed in any manner well known to those skilled in the art. The sulphuric acid is sprayed into the chamber 27,-by any desired acid spray device 28, through the top of the chamber. The resulting ammonium sulphate is produced according to the following equation:

An outlet 29per1nits removal of the ammonium sulphate, the latter being ,removed to conventional crystallizing and drying arrangements 30. The dried ammonium sulphate material is then fed back into the hopper 5 with fresh quantities of potassium chloride. A continuous, and complete, cycle is thereby established for the conversion of potassium chloride into potassium sulphate, and the utilization of conversion by-products in producing ammonium sulphate. v

Another important advantage of the present process resides in the fact that'a portion or all of the liberated ammonia gas of chamber 22 may be diverted for use inV the production of potassium nitrate from the potassium sulphate. Thus, by oxidizing the ammonia to form nitric acid, according to methods well known to` those skilled in the art, the acid may be used for dissolving calcium carbonate according to the equation:

The calcium nitrate solution is, then reacted with potassium sulphate, issuing through outlet 8, according to the following equation:

The aforementioned reaction has been disclosed in my said co-pending application, and is claimed therein. It is mentioned herein to demonstrate the manner in which the potassium sulphate produced by the present process is converted into the desirable potassium nitrate.

While'llr have indicated and described only one arrangement, and series of steps, for utilizing my present discovery, it will be clear to one skilled in the art that my invention is by no means limited to the particular steps, or means, shown and described, but that many modications, both in sequence of steps and type of apparatus, may be used without departing from the scope of my invention as set forth in the appended claim.

What I claim is:

A method of producing potassium sulphate consisting. in slowly passing a reacting mixture monia in sulphuric acid and using the recovered l solid ammonium sulphate for the conversion of additional quantities of potassium chloride.

AUGUST HOLZ. 

